Conventionally, various techniques are developed in order to help improve an environment in a cabin by using an air conditioner etc. For example, Japanese Patent Application Publication No. 2004-276731 (JP 2004-276731 A) discloses a technique of displaying animation of three-dimensional airflow to show how air is blown. Japanese Patent Application Publication No. 2003-146055 (JP 2003-146055 A) discloses a technique of displaying temperature distribution in a cabin.